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The Physiology I of the Pigmentary System TPS01 1/21/06 5:08 PM Page 2 TPS01 1/21/06 5:08 PM Page 3

Historical and Comparative 1 Perspectives of the Pigmentary System TPS01 1/21/06 5:08 PM Page 4 TPS01 1/21/06 5:08 PM Page 5

A History of the Science 1 of Pigmentation Sidney N. Klaus

In retrospect, it is clear that the science of skin color had Introduction completed its early phase of development by the 1840s. With the discovery of the cellular nature of the epidermis, the In Europe, prior to the seventeenth century, notions about “modern” phase of skin color science had begun (Meirowsky, the origin of human skin color were based largely on myths 1940). This chapter briefly summarizes the first 250 years of and fanciful stories passed down from the ancient world. The the earlier phases of pigment research, from its birth in the stories focused on providing explanations for the blackness of 1600s to its “coming of age” in the 1840s. A history of the Africans. Europeans with an ethnocentric perspective thought modern era, from the 1840s to the present, may be found in that it was necessary to justify the darkness of outsiders rather reviews by Becker (1959) and Nordlund et al. (1989). than to explain their own paleness. In Europe, two theories about the origin of Africans’ color predominated. The first proposed that the black hue of African skin was a consequence Early Anatomic Discoveries of the intense sunlight and heat to which Africans were exposed. The second idea proposed that African color was a To the ancient Greeks and Romans who were acquainted with result of divine intervention, a concept that stemmed from the the peoples of Ethiopia, the black color of the Africans was well-known passage in Genesis describing Noah’s curse on regarded as their most characteristic and most curious feature. Ham and his progeny. Greek and Roman scientists were not equipped to investigate Such traditional views of skin color were questioned during the causes of dark complexions in a meaningful way. They the Age of Discovery. Explorers were returning home from understood little about dissection of individual tissues and remote regions of the globe and bringing with them descrip- were unable to sort out the anatomic details related to the tions of black-, yellow-, or red-hued peoples. The array of skin. They regarded the skin as an amorphous membrane colors fascinated scientists and excited them to investigate made from the congealing of “moist exhalations” driven to how these skin colors originated. the surface of the body by internal heat. They believed that During the sixteenth century, the scientific community pre- the color of skin was imposed either from outside by the sun pared for this task. Scientists learned new techniques of human or by some inner humor. These notions about skin color per- dissection and new methods of chemical analysis. More sisted through the Middle Ages and into the Renaissance. In importantly, they adopted a new philosophical approach for 1543, Vesalius succeeded in splitting the skin into two layers the study of natural phenomena. Rather than analysis of phe- by applying a burning candle to the abdomen of a living nomenon based on a priori assumptions, they based their subject. He did not examine the skin layers for their content analyses on firsthand observations and experimentation. By of color. It was not until 75 years later that the first “scien- the seventeenth century, anatomists and physicians had begun tific” study of skin color was performed. to collect objective data about skin color. For the next two In 1618, Jean Riolan the younger, a Parisian anatomist, was centuries, so many important observations had been collected the first person to make a detailed analysis of skin color. He about the seat of skin color and the causes of its diversity that, used a technique similar to that of Vesalius to separate the skin as one researcher boasted, “a good sized volume was scarcely of a black subject into two layers. But he used a vesicant rather large enough to contain them.” than a flame to produce a blister and carefully examined the The furious pace of forward progress was slowed somewhat two layers for their color and texture. He found that, while in the early part of the nineteenth century when skin color sci- the top of the blister (the cuticle) was pigmented, the base (the entists in both Europe and America were drawn into acrimo- cutis) remained white. “Color . . .” he announced “. . . lay in nious debates over social issues, especially slavery and the the outer layer, and did not go so deep as the true skin” place of “peoples of color” in the family of man. By the end (Riolan, 1618). of the century, the slavery issue had been settled, and the dis- To Riolan, this finding reinforced the idea that heat and sun- covery of the cell and improved methods for the microscopic light were the ultimate causes of blackness. Riolan reasoned examination of the skin had stimulated the discipline to set that, if the sun caused skin darkening, it was expected that the off in new directions. outer cuticle would be darker than the inner cutis.

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A few years later, Alexander Read, an anatomist working planted out of Africa, retain still the complexion of their Prog- in London, repeated Riolan’s experiments and found the same enitors” (Boyle, 1664). results. However, Read offered a different interpretation. The skin pigment, he concluded, was not caused by singeing the body’s surface. He concluded rather that skin color was Malpighi’s Innovation: derived from the body’s inner humors. As they escaped the Rete Mucosum through the skin, some of the elements became attached to the surface and dried, thus producing the pigment. Negroes, he Riolan’s contention that the cuticle was the seat of color had argued, had darker skin because they had larger pores than been in place for less than a century when it was superseded whites, a morphologic variation allowing greater volumes of by an entirely different notion proposed by the Italian their humors to escape leaving behind larger amounts of black anatomist, Marcello Malpighi. In 1667, Malpighi stated that “remnants” of the humors (Read, 1642). the seat of color was not the cuticle. Rather, he proclaimed Perhaps the most detailed analysis of skin color in the sev- that color was located in a separate layer of the skin enteenth century was carried out by the distinguished writer sandwiched between the cuticle and the cutis. He named this and physician, Sir Thomas Browne. Browne had listened care- layer the rete mucosum. The discovery of rete came about fully to the accounts of explorers who had found variously in the following way. In 1665, Malpighi had been searching colored races, and he concluded from these accounts that color for the structures that mediated the sensation of taste, and he did not arise from the influence of climate. “If the fervor of succeeded in finding large papillae just below the surface of the Sun were the cause of the Negroes’ complexion, . . .” he the tongue. Turning to the skin to see if he could find similar wrote, “. . . it is reasonable to assume that inhabitants of the structures that mediated touch, he found that he was unable same latitude, subjected unto the same vicinity of the Sun, to separate the skin’s layers properly by boiling, the method partake of the same hue and complexion, which they do not.” that he had used previously. He was forced to use putre- In addition, he noted that Africans who had been transplanted faction, an old dissection technique in which the separation of into “. . . cold and phlegmatic habitations . . .” had not turned parts is enhanced by allowing a small piece of tissue to decom- white, but “. . . continued their hue, both in themselves and pose partially. Using this method, he prepared skin from their generations.” He rejected the idea that skin blackness cadavers and found that he could easily lift the cuticle from was acquired from a “. . . power of imagination . . .” or the cutis. By this method, he was able to identify the dermal from “. . . anointing with bacon and fat substances.” Instead, papillae. However, he also found a mucoid material draped he thought that the tincture of the skin was based on an inborn over the papillae, which he regarded as a protective covering. trait, a trait that was passed from father to son by the The material had a netlike appearance when seen from sperm. above, so he called it the rete mucosum. Malpighi’s experi- Browne was not an armchair scientist. His diary records the ments were not directed at discovering the proximate cause outline of numerous experiments he carried out to determine of skin color. However, in one experiment in which he for himself the seat of color. For example, he set out to make used skin from an Ethiopian cadaver, he noted that the mucoid a “. . . blistering plaster in a negroes skinne and trie if the next material was tinged black. On the basis of this finding, he skin will bee white . . .” and to see whether a “. . . vesication later wrote “It is certain that the cutis (of the Ethiopian) is will do anything upon a dead cold body.” He even urged his white, as is the cuticula too; hence all their blackness arises son Edward, a medical student, to carry out additional studies. from the underlying mucous and netlike body” (Malpighi, He wrote to him asking that he “. . . separate the skin of 1665). a black person with boiling water and take notice of the Malpighi did not follow up on his discovery of the “seat of cuticula and cutis and observe how the scarres become whiter color” but the putrefaction technique he used allowed the or less blacke than any other parts.” He also urged him to layers of the skin to be separated gently. The method produced “. . . touche the skin with aqua fortis and see how it will alter reliable results, and other investigators soon expanded on the colour.” Unfortunately, Browne did not record the results Malpighi’s finding. In 1677, three years after Malpighi pub- of these experiments (Keynes, 1964). lished his findings, Johann Pechlin, a Dutch anatomist, used Another seventeenth century polymath, Robert Boyle, Malpighi’s method of dissection to make a thorough study of devoted a chapter of his book Experiments and Considera- Ethiopian skin. In one experiment, after he lifted off the tions Touching Colours to what he called “the Cause of the cuticle, he scraped away the black mucous and reapplied the Blackness of those many nations which by one common scarf to the cutis. He reported that “. . . a whiteness came forth Name we are wont to call Negroes.” He examined the various immediately of the sort seen often enough in Europe. In truth causes proposed at that time and denied that either Noah’s the surface of the skin was scarcely unattractive.” Pechlin was curse on Ham or “heat alone” could produce a true concerned that his results obtained using cadaver skin might blackness. Instead, he focused on principles of inheritance, not be the same had he studied living skin. To his dismay, he concluding that the “Principal Cause of the Blackness of was unable to convince living subjects to cooperate in his Negroes is some Peculiar and Seminal Impression.” As experiments “. . . because of I don’t know what sort of evil on evidence, he reported that “the off-spring of Negroes, trans- the part of the Negroes” (Pechlin, 1677).

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A few years later, the Dutch microscopist Antoni van that he had examined cadavers of Africans and observed that Leeuwenhoek, in a letter to the Royal Society of London, “the bile is black, and the blackness of the skin is in propor- reported on his observations made using his microscope of the tion to the blackness of the bile.” skin of a black Moorish girl. “I took from several parts of the Later in the century, another investigator attempted to arms the outer skin with a fine little instrument and found that prove that the pigment of Africans was derived from bile. it consisted of little scales. Putting these scales before my Samuel Stanhope Smith, a professor of moral theology at the microscope I found them to be not as transparent as those of College of New Jersey, had learned from an American col- my skin.” Van Leeuwenhoek concluded that the black color league that bile exposed to the sun and air changed its color of the skin was the result of the black scales, and that “the to black. Smith hypothesized that, in southern climates, the little vessels which form the scales of the Moors” may possi- secretion of bile was augmented and, when the bile reached bly develop a slightly darker color (Collected Letters of Antoni the skin, it became “. . . more languid and almost fixed.” van Leeuwenhoek, 1683–1684; see Schierbeek, 1952). In the skin, the aqueous parts of the bile easily escape through If one follows Malpighi’s directions for uncovering the rete, the pores of the skin by perspiration, while the more dense as the cuticle is lifted off one observes tiny mucoid threads portion remained in a glutinous state within the rete. There, bridging the angle between the two layers. William Hunter it received the repeated radiation from the sun and atmosphere described them as “. . . an infinite number of filaments, as fine and turned black. Smith believed that a cold environment as the most delicate threads of a spider’s web, that pass would reverse the process of darkening and render the com- between the cutis and the more external integuments” plexion “. . . clear and florid.” According to Smith, if Africans (Hunter, 1764). According to some anatomists, the threads moved to temperate climates from Africa “. . . they would were tiny vessels. This idea led some of the more inventive soon lose their imposed color and become the color of investigators to propose that the coloring matter in Africans’ Europeans” (Smith, 1788). skin was not the mucous material itself but was a black fluid Johann Friedrich Blumenbach, the German ethnologist, also contained within the web of small vessels. One contemporary proposed that bile was the coloring agent of the skin. He observer wrote “. . . between the outward and inner skin of had learned that bile was made of a mixture of carbon and the corpse can be found a kind of vascular plexus, spread over hydrogen. He suggested that, as the bile reached the skin, the the whole body like a web or net, which was fill’d with a Juice hydrogen it contained became more volatile than the carbon as black as Ink” (Marana, 1801). and combined with atmospheric oxygen. This reaction left It became something of a challenge to prove unequivocally behind a black carbon residue that became embedded in that these filaments were in fact “vessels.” In anatomic labo- the Malpighian mucous and caused the skin to darken ratories, the identification of small vessels in anatomic prepa- (Blumenbach, 1865). rations relied on their visualization after they had been Another “chemical” theory was advanced by the young injected with colored glue or isinglass. Only a few investiga- Humphrey Davy in 1799. Davy thought that light had a great tors were skilled enough to inject these “. . . most delicate affinity for oxygen and could extract it from other com- threads.” One anatomist who was given credit for the first pounds. Davy had evidence that the mucous material of the demonstration of this vascular network was William rete was made of a colorless mixture of carbon, nitrogen, and Baynham, an American who had moved to London in 1769. oxygen. He proposed that sunlight extracted the oxygen from Although Baynham never published his findings, he placed his this mixture and left behind a black material made of carbon specimens on exhibition in John Hunter’s anatomic museum. and nitrogen. To Davy, this explained differences in skin hues Not all Baynham’s colleagues were convinced by his discov- found throughout the world. “In northern latitudes, where the ery. William Cruickshank made a careful study of Baynham’s inhabitants are less exposed to light, the rete continues to preparations and later wrote that he was “. . . not perfectly contain its full proportion of oxygen, and the inhabitants are satisfied” with them. He concluded that Baynham had not lighter in color. In the torrid zone, on the other hand, where injected the vessels of the rete, but rather a series of vessels the sun was especially intense, larger quantities of oxygen that lay between the rete and the cutis (Cruickshank, 1795). would be removed, and the blackness peculiar to the negroes In the eighteenth century, the attention of researchers began will be found.” Davy had no direct proof that light could sub- to move from the anatomy of the rete to the “nature” of the tract oxygen from the skin, but he did cite other chemical coloring matter itself. Early attempts to collect and analyze experiments to support his claim. He reported that, when a material from the rete were not productive. Alexis Littre, a compound that binds oxygen, such as sulfur of potash, is French surgeon, soaked pieces of skin from a Negro cadaver applied to the skin of a white person, the skin blackens. When for a week either in warm water or in spirits of wine but was a compound that gives off oxygen, such as muriatic acid, is unable to extract any of the coloring matter (Littre, 1720). applied to the skin of a Negro, it lightens (Davy, 1799). A few years later, another French scientist, Pierre Barrere, An even more imaginative notion about the nature of skin in an essay submitted to the Academy of Bordeaux in 1741, color was suggested by Immanuel Kant. Kant based his theory denied Malpighi’s claim that the pigment of Africans’ skin on the well-known capacity of phlogiston to turn blood a arose from the “corps reticulaire.” It is evident, he wrote, the black color. Phlogiston was an imaginary element considered coloring matter in the skin of Africans was bile. He reported to be the essential principle of combustion. It was said to be

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released from the body through the lungs as part of the meta- Bolstering the polygenist cause was the English anatomist, bolic process. Kant believed that, in regions of the globe where John Gordon. Gordon claimed that whites, unlike blacks, had the atmosphere was heavily phlogisticated, such as the coast no rete mucosum. “I have satisfied myself by many dissection of Africa, it would be impossible to eliminate all the body’s that in the Negro there is a Black membrane interposed phlogiston by breathing. Kant proposed that the excess phlo- between the epidermis and true skin upon which their dark giston would travel through the circulation and, on reaching color entirely depends ...But after the strictest examination I the skin, it would precipitate in the ends of the small cuta- have not been able to find any light colored rete mucosum in neous vessels and turn the skin black (Lovejoy, 1959). the inhabitants of Great Britain, nor in those of other nations Claude Le Cat, a French physician, claimed that the source resembling them in color” (Gordon, 1815). of Africans’ blackness was neither bile nor blood. He said that Several anatomists disagreed. Richard Harlan, a young lec- the black mucous, which he called ethiops, was found only in turer in anatomy from Philadelphia, wrote that “. . . the exis- Africans and that it was secreted directly into the skin through tence of the rete mucosum in the white race, so frequently the tips of the cutaneous nerves (Le Cat, 1765). denied, has been demonstrated occasionally in the European Although most early scientists believed that skin pigment by skilful anatomists and if not deceived I myself have dis- was derived from some “internal” source such as bile or covered it several times in a living European subject, by raising blood, a few investigators decided that the coloring matter was the epidermis with a blister, especially upon the back of the produced by glands within the skin itself. The earliest version hands and the neck” (Harlan, 1835). of this hypothesis was offered by an English anatomist, Charles Caldwell, who had moved from Philadelphia Edward Tyson. He proposed that the black colour in Negroes’ to become a professor in a medical college in Lexington, skins came from glands that were full of a “black liquor.” He Kentucky, reported that he too found the rete in both races, suggested that the climate might alter the glands so that “. . . although the structures were not identical in appearance. “The they might separate from the mass of blood a differing humor rete mucosum in blacks is comparatively thick, while in the from White, and by this means give a different hue to the Caucasian, the rete is present but it is much thinner.” In spite inhabitants” (Montagu, 1943). of this similarity, however, Caldwell concluded that Negroes Two French researchers, G. H. Breschet and Roussel de and Caucasians were sufficiently distinct to be called separate Vauzeme, reported that they had found a “. . . chromatogen- biological species (Caldwell, 1830). ous apparatus . . .” in the cutis which secreted the black mucous. They said that the mucous was deposited on the surface of the dermal papillae through short, excretory ducts Experiments of Nature emanating from glandular parenchyma located in the cutis (Plumbe, 1837). In addition to the work carried out by anatomists and chemists Another French investigator, M. Gaultier, also argued that in dissecting rooms and laboratories, many physicians made the coloring matter was secreted within the skin but not from important contributions to the fund of information about skin glands. The pigment of the skin, he said, was produced instead color through reporting and analyzing patients with clinical from hair bulbs. Gaultier’s claim was based on the results of problems. John Josselyn, a physician from England who was an experiment he carried out on a living subject. He burned visiting the Massachusetts Bay Colony in 1675, was one of the skin of a Negro and then closely observed the pattern the first physicians to advance the science of skin color by of repigmentation during the healing process. According to using observations based on a clinical case. While in Boston, Gaultier, the pigment appeared first around the “pores” Josselyn had been called upon to lance a “corruption” in the through which the hairs exited and only later did it radiate palm of a “Moor.” Later, he described his findings. “After I out to cover the entire area of the burn (Prichard, 1813). lanced it, I perceived that the Moor had one skin more than Englishmen, deeper in colour than our European veins, and upon it rests the epidermis” (Josselyn, 1675). Differences Between Blacks and Whites Samuel Marcy, a physician from rural New Jersey, reported the case of an albino girl. After providing a full account of her As a more complete picture of skin color began to emerge by family history, including the fact that she had two albino the end of the eighteenth century, political and social forces sisters, he went on to consider the cause of the disorder. “The required the disciplines of anatomy and biology to take on a mother accounts for the appearance of the child by attribut- social dimension. Advocates of black slavery argued that ing it to a severe fright she receive by the falling down of an Africans were not the “brothers” of Europeans but rather old white mare she was driving,” wrote Marcy. “Although I were the product of a separate creation. Skin color, the most was unwilling to admit at first that the Great Creator ever left obvious marker of racial identity, was forced to the center of his work in so loose a manner, that the imagination of the the debate over the unity of mankind. The polygenists began mother should alter or determine form or color of her chil- looking for “significant” anatomic differences between blacks dren, the birth of two other albino children go further to and whites to prove they were separate species. Monogenists strengthen the doctrine that the mind of the mother may affect began looking for evidence of similarities. the fetus in utero” (Marcy, 1839).

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John Morgan, from Philadelphia, reported the case of He decided to study Moss in detail. “Anxious to know as Adelaide, a pied Negro girl from the West Indies. Like much of his case as possible, I took him in some measure under Marcy, Morgan considered the possibility that maternal my care, . . . and . . . for a slight reward made on him such impression might cause the disorder. Morgan related that, experiments as suited my purpose. While thousands visited while pregnant, the mother of the girl “. . . delighted in laying and gazed at Moss as an object of curiosity and wonder, I out all night in the open air, and contemplating the stars and alone endeavored to make him a source of scientific informa- planets. Whether the strong impression made upon the mother tion.” Caldwell asked Moss “. . . to excite by exercise a of Adelaide by the nightly view of the stars and planetary copious perspiration to ascertain whether the fluid perspired system may be the cause of the very extraordinary appearances by the colored portions of the skin was itself colored. And I in this girl, everyone will have to determine for themselves” found that it was not.” Caldwell examined Moss’ skin and (Morgan, 1784). found that the rete mucosum had disappeared from the depig- During the seventeenth and eighteenth centuries, the mented areas. He concluded that the rete had been removed pigment disorder that attracted most attention among the “. . . by means of absorption.” Moss’ sensitivity to low tem- medical community, as well as the general public, was peratures he thought supported his theory that Moss was vitiligo vulgaris. In 1697, a remarkable case was presented to losing his rete. He concluded that Moss’ true skin was now the Royal Society by William Byrd, a Virginian who had “protected” from a cold atmosphere by nothing but the cuticle recently returned to London after a visit home. Under the title (Caldwell, 1855). “An Account of a Negro-Boy that is dappeld in several Places Samuel Stanhope Smith, who had earlier pioneered the idea of his Body with White Spots,” Byrd reported that the that African blackness was caused by environmental factors, boy was born in Virginia of black parents, who was “well was another visitor. He was accompanied by two other gen- till 3 years old, and now was speckled of his breast and back tlemen “. . . of whom none are more capable of observing a and that no fancy had taken his Mother.” The spots he fact of this nature with a sound and accurate judgment.” wrote are “wonderfully White, at least equal to the skin of the Smith paid great attention to the pattern of Moss’ pigment fairest Lady. His Spots grow continually larger and larger, and loss and concluded that this provided elegant proof of his ’tis probable, if he lives, he may in time become all over hypothesis. “Although there was evidently a strong and white.” Thomas Jefferson described an African slave whom general tendency in the constitution of this negro to a change he encountered on his own plantation. He described the man of color, yet this tendency was much longer resisted in those as “A Negro man within my knowledge, born black and of parts of the body which were most exposed to the immediate black parents, developed when a boy, a white spot on his chin. action of the sun’s rays. As he was a laboring man, wherever This continued till he became a man, by which time it had there were rents in the thin clothes which covered him there extended over his chin, lips, and the neck on that side. He were generally seen the largest spots of black.” From this is robust and healthy and the change of color is not accom- pattern, Smith inferred that “. . . where any dark color has panied with any sensible disease, either general or topical” been contracted by the human skin, the solar influence alone, (Jefferson, 1904). and the free contact of the external air, will be sufficient to Charles Peale, the painter and natural historian, also continue it a long time even in those climates which are most described a case under the title “An Account of a person born favorable to the fair complexion” (Smith, 1810). a Negro who afterwards became white” (Peale, 1791). Benjamin Rush suggested perhaps the most unusual hypoth- The case of vitiligo that attracted most attention during esis to explain Moss’ pigment loss. In a paper published in this period from both lay and medical communities was Mr 1799, Rush argued that it was the blackness of Moss, and not Henry Moss. At the age of 38 years, Moss first noted a change his white spots, that represented his disease. I shall prove, he in the color of his skin. The change began on his fingers and wrote, that “. . . the color and figure of our fellow creatures hands and extended over his arms, legs, and face. Six years who are known by the epithet of negroes are derived from a later, in the summer of 1796, Moss traveled from his home in modification of that disease which is known by the name of Maryland to exhibit himself for money at the Black Horse Leprosy.” Rush went on to explain that the black color of the Tavern in Philadelphia. He became a popular attraction and, negroes, their thick lips, and their insensitivity to pain were according to one account, was so well known to the local all common signs of leprosy. He suggested that it was likely citizens “. . . that his name was almost as familiar as John that leprosy was an infectious disorder “. . . since a white Adams, Thomas Jefferson, or James Madison” (Caldwell, woman in North Carolina living with a black husband has not 1855). only acquired a dark color but also several features of a Several prominent physicians from Philadelphia visited Mr negro.” Rush proposed that Moss was not suffering from a Moss. Benjamin Barton, a professor at the medical school, was disease but was actually undergoing a spontaneous cure of impressed with the distribution of the white spots. Noting that one. “If the color of negroes is a disease . . .” he added, “. . . Moss’ color had disappeared completely from his armpits, let science and humanity combine their efforts and endeavor Barton suggested initially that it was likely that the pigment to discover a remedy for it.” From his experience with other had been washed away by perspiration. Charles Caldwell also ailments, Rush suggested that bleeding or purging be tried to examined Moss and was skeptical of Barton’s interpretation. lessen the black color (Rush, 1799).

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Josselyn, J. An Account of Two Voyages to New-England. London: G. Widdowes, 1675. The Beginnings of Modern Keynes, G. The Works of Sir Thomas Browne. Chicago: University of Pigment Research Chicago Press, 1964. Le Cat, C. N. Traite de la Couleur de la Peau Humaine en General, The “early” phase of pigment research ended in the 1840s de celle des Negres en Particulier, et de la Metamorphose d’une de when the cell theory ended the rete’s reign as a separate amor- ces Coleurs en l’autre, soit de Naissance, soit Accidentellement. Amsterdam, 1765. phous layer of the skin and assigned the seat of skin color Littre, A. La Peau in Histoire de l’Academie Royale des Sciences. to the lower portion of a cell-rich epidermis. Microscopic Paris: Hochereau, 1720, pp. 30–32. anatomists had also discovered that the pigment was not in Lovejoy, A. O. Kant and Evolution in Forerunners of Darwin. the form of a liquid or mucoid material but was rather com- Baltimore: Johns Hopkins, 1959, pp. 173–206. posed of tiny intracellular granules. With the discovery that a Malpighi, M. De Externo Tactus Organo Anatomica Observatio. Naples: Apud Agidium Longu, 1665. population of dendritic cells derived from the neural crest Marana, G. P. Letters Written by a Turkish Spy, vol. 8. London: served as the source of the coloring matter for the skin and Vernor and Hood, 1801. hair, the “modern” phase of pigment research moved into high Marcy, S. S. On the albino. Am. J. Med. Sci. 24: 517–518, 1839. gear. For the past 150 years, researchers have relied on a Meirowsky, E. A critical review of pigment research in the last melanocyte-centered paradigm to lead them along new paths hundred years. Br. J. Dermatol. 52: 205–217, 1940. Montagu, M. F. A. Edward Tyson, MD, FRS, and the Rise of Human of discovery. To see how far their investigations have pro- and Comparative Anatomy in England. Philadelphia: The Ameri- ceeded and how wide-ranging their interests and disciplines, can Philosophical Society, 1943, pp. 212–213. one needs only to look through the remaining chapters in this Morgan, J. Some account of a motley coloured, or pye, negro girl and volume. mulatto boy. Trans. Am. Phil. Soc. 2: 392–395, 1784. Nordlund, J. J., Z. A. Abdel-Malek, R. E. Boissy, and L. A. Rheins. Pigment cell biology: An historical review. J. Invest. Dermatol. References 92(Suppl.): 53s–60s, 1989. Becker, S. W. Historical background of research on pigmentary dis- Peale, C. W. Account of a person born a negro, or a very dark mullato, eases of the skin. J. Invest. Dermatol. 32: 185–196, 1959. who afterwards became white. Univ. Asylum Columbia Mag. 2: Blumenbach, J. F. The Anthropological Treatises of Johann Friedrich 409–410, 1791. Blumenbach. London: Longman Green, 1865. Pechlin, J. N. Du Habitu & Colore Aethiopum Qui Vulgo Nigritae. Boyle, R. Experiments and Considerations Touching Colours. Koln: Joach Reumani, 1677. London: Henry Herringman, 1664, pp. 151–167. Plumbe, S. A Practical Treatise on the Diseases of the Skin. London: Caldwell, C. Thoughts on the Original Unity of the Human Race. Sherwood, Gilbert & Piper, 1837, pp. 9–16. New York: E. Bliss, 1830. Prichard, J. C. Researches into the Physical History of Man. London: Caldwell, C. Autobiography of Charles Caldwell, MD. Philadelphia: John and Arthur Arch, 1813, pp. 163–164. Lippincott, Grambo and Co., 1855. Read, A. The Manual of the Anatomy or Dissection of the Body of Cruickshank, W. Experiments on the Insensible Perspiration of the Man. London: Francis Constable, 1642. Human Body. London: George Nicol, 1795. Riolan, J. Anthropographia. Paris: Hadrianum Perier, 1618. Davy, H. Essays on heat and light. In: Contributions to Physical and Rush, B. Observations intended to favour a supposition that the black Medical Knowledge Principally From the West of England, T. color (as it is called) of the negroes is derived from leprosy. Am. Beddoes (ed.). Bristol: Biggs and Cottle, 1799, pp. 193–198. Philos. Soc. Trans. 4: 289–297, 1799. Gordon, J. A System of Human Anatomy. Edinburgh: William Schierbeek, A. (ed.). Collected Letters of Antoni van Leeuwenhoek, Blackwood, 1815. Vol. IV, 1683–1684, Amsterdam: Swets & Zeitlinger, 1952, pp. Harlan, R. Medical and Physical Researches. Philadelphia: Lydia 245–251. Bailey, 1835. Smith, S. S. An Essay on the Causes of the Variety of Complexion and Hunter, W. Remarks on the cellular membrane and some of its dis- Figure in the Human Species. Edinburgh: C. Elliot, 1788. eases. Med. Observ. Inquiries 2: 26–55, 1764. Smith, S. S. An Essay on the Causes of the Variety of Complexion and Jefferson, T. Notes on Virginia, in the Writings of Thomas Jefferson. Figure in the Human Species. New Brunswick: J. Simpson and Co., Washington, DC: Thomas Jefferson Memorial Association, 1904. 1810.

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